On orbit 48, after 75 hours of flight a problem arose. During a pass over the continental US the flight computer was updated. McDivitt was told to switch off the computer. He flipped the switch but the computer did not turn off. On the ground at mission control, efforts to solve the problem began immediately. For the next few orbits, the crew received instructions for trying different switch positions, after all the switching the computer finally failed entirely and could not be turned back on. Now the astronauts would have to resort to a rolling Mercury-type reentry, rather than the lifting bank angle the computer was supposed to help them achieve…

For the first time Television coverage of the launch had an international audience, as the scene was broadcast to 12 European nations via Intelsat 1 aka the Early Bird satellite of episode 59. Heightened by the prospect of an EVA and the first use of the new Mission Control Center in Houston, interest in Gemini IV reached levels never again matched in the Gemini program…

The success of Gus Grissom and John Young’s Gemini 3 flight paved the way for long duration space missions. The longest U.S. manned space flight to date was Gordon Cooper’s 34 hour Mercury flight. The Soviets, however, had four long duration flights to their credit, ranging from 70 to 119 hours. It was time for the US to attempt a long duration flight.

On January 3 1962, “Gemini” became the official designation of the Mercury Mark II program. The name had been suggested by Alex Nagy of NASA Headquarters because the twin stars Castor and Pollux in constellation Gemini (the Twins) seemed to him to symbolize the program’s two-man crew, its rendezvous mission, and its relation to Mercury. Coincidentally, the astronomical symbol (II) for Gemini, the third constellation of the zodiac, corresponded neatly to the Mark II designation…